Cisco · Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD)

CVE-2024-20353

Cisco ASA and FTD Denial of Service Vulnerability

Evidence

Source & freshness

Full source status →

CISA KEV catalog Core KEV record

CVE, vendor/product, CISA dates, ransomware status, description, required action, and notes.

Catalog 2026.07.24 · Retrieved 2026-07-25 20:49 UTC Open official CISA feed ↗

MITRE CWE catalog CWE context

CWE names and plain-language weakness descriptions. CISA supplies the CWE assignment itself.

Retrieved 2026-07-25 20:59 UTC Open official MITRE CWE catalog ↗

National Vulnerability Database NVD technical context

CVSS metrics, NVD timeline, and related NVD record data are stored locally.

Retrieved Jul 25, 2026, 08:49 PM UTC Open NVD record ↗

CISA KEV record

CISA date added: 2024-04-24
CISA due date: 2024-05-01
Known ransomware use: Unknown

NVD risk context

8.6 HIGH

CVSS is a technical severity score. CISA’s KEV status remains the evidence that this vulnerability is known to be exploited.

View NVD record ↗

Attack vector

Network

The vulnerable service can be reached remotely over a network.

Attack complexity

Low

Exploitation does not require unusual conditions beyond normal attacker control.

Privileges required

None

The attacker does not need an existing account or privileges.

User interaction

None

No action by another user is required.

Description

Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) contain an infinite loop vulnerability that can lead to remote denial of service condition.

Required action

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

NVD reference index

Vendor and remediation references

NVD has tagged these sources as vendor advisories, patches, mitigations, or release notes.

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-websrvs-dos-X8gNucD2 ↗
Vendor Advisory NVD reference source: psirt@cisco.com · Also linked in CISA notes

Other NVD references (2)

https://blog.talosintelligence.com/arcanedoor-new-espionage-focused-campaign-found-targeting-perimeter-network-devices/ ↗
ExploitThird Party Advisory NVD reference source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-20353 ↗
US Government Resource NVD reference source: 134c704f-9b21-4f2e-91b3-4a467353bcc0

MITRE CWE context

CWE classification

CWE-835 Loop with Unreachable Exit Condition ('Infinite Loop')

The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.

View official MITRE CWE details ↗

NVD record timing

NVD record timeline

These dates describe NVD’s record, not CISA’s KEV addition or remediation due date.

NVD published: Apr 24, 2024, 07:15 PM UTC
NVD last updated: Jun 17, 2026, 07:06 AM UTC

Advanced: view the technical CVSS vector

This standardized code is intended for security tools and technical analysts. The plain-language risk summary above explains its main points.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

View NVD record ↗

CISA notes

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-websrvs-dos-X8gNucD2; https://nvd.nist.gov/vuln/detail/CVE-2024-20353